Plastic film bag with tear tapes

ABSTRACT

A plastic film bag, including a seam welded part, a plastic film bag body part, and a tear tape to open the plastic film bag, is disclosed. In the plastic film bag, the tear tape is made of a monodirectionally oriented polypropylene film and is attached to an outer surface of the plastic film bag at a predetermined position between the seam welded part and the plastic film bag body part. Because the plastic film bag of the present invention is realized such that the tear tape is attached to the outer surface of the plastic film bag using an adhesive, the tear tape does not compromise the function of sealing the package, but allows the package to be completely sealed, unlike a conventional tear tape attached to the inner surface of a plastic film bag.

RELATED U.S. APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO MICROFICHE APPENDIX

Not applicable.

FIELD OF THE INVENTION

The present invention relates, in general, to bags made of plastic films and provided with tear tapes and, more particularly, to a plastic film bag which can be opened using tear tapes and can be completely sealed despite the tear tapes being provided on the film bag.

BACKGROUND OF THE INVENTION

Plastic film bags, which are shaped as bags using plastic films as shown in FIG. 1, have been widely used as packaging materials to package a variety of foods, such as processed food or snacks, in recent years.

In the prior art, the plastic film bags to package food may be produced by cutting a long tubular plastic film, which is continuously extruded from an extruder, into a plurality of tubular pieces having predetermined lengths and by seaming the cut ends of each tubular piece of the film through high frequency seam welding. Alternatively, the plastic film bags may be produced by placing two plastic films such that one overlaps another, and by thermally seaming the four sides of the two overlapping films, thus shaping the overlapping films in a bag.

The plastic films, used as the materials of the plastic film bags, may be selected from films 100-200 μm in thickness made of polyethylene resin, polypropylene resin, polyester resin or nylon resin, or papers impregnated with one of the synthetic resins. Products, packaged in the plastic film bags, are marketed in the state of being contained in the vacuum-sealed bags. When it is required to use the packaged products, users open the vacuum-sealed plastic film bags and take the contents out of the open bags to use the contents.

To open a conventional vacuum-sealed plastic film bag, a user may directly cut the upper end of the bag using scissors. Alternatively, a plastic fastener may be provided on the inner surface of the plastic film bag to allow a user to repeatedly close the open end of the bag after the end of the bag has been cut. As a further alternative, to allow a user to open a vacuum-sealed plastic film bag, the bag may be constructed such that it may be opened in a conventional manner which has been adapted to plastic films used to package cigarette packs.

Generally, the plastic films that package cigarette packs are made of polypropylene resin. To allow users to open the plastic films of the cigarette packs when necessary, tear tapes are attached to predetermined portions of the films using an adhesive along which the films may be cut and open. When a user pulls a tear tape forcibly backwards along a predetermined tear line of the polypropylene film, the film is cut and opened along the predetermined tear line by the force of pulling the tear tape backwards. The manner of cutting and opening a plastic film using a conventional tear tape will be described herein below with reference to FIG. 1. A tear tape 3 is provided along a predetermined tear line on the inner surface of the plastic film bag 1 such that one end of the tear tape 3 protrudes outside the film bag 1. Thus, when a user holds the protruding end of the tear tape 3 with fingers and pulls the tear tape 3 backwards along the predetermined tear line of the film bag, the tear tape 3 presses the film 2 along the predetermined tear line along which the tear tape 3 is attached. Therefore, the plastic film 2 is cut and opened along the predetermined tear line.

However, the manner of cutting and opening a plastic film using a conventional tear tape is problematic in that a tear tape must be attached on the inner surface of the polypropylene film using an adhesive and, furthermore, one end of the tear tape must protrude outside the plastic film so as to allow a user to hold the end of the tear tape and pull the tear tape backwards so as to cut and open the plastic film.

In the manner of cutting and opening a plastic film using a conventional tear tape, the tear tape is attached to the inner surface of the film using an adhesive, and part of the tape must pass through the film so as to protrude outside the film. Thus, this manner cannot completely seal the package.

Thus, although the manner using a conventional tear tape has been recognized as a simple and easy manner, it is not preferably adapted to package some foods, for example, precooked food, stuffed pancakes, bread, or fast food, the quality of which may be greatly reduced when the food in the package is gradually dried or comes into contact with atmospheric air.

To solve the above-mentioned problems, it has been required in the related art to provide a plastic film bag which uses a tear tape and completely seals a packaged item from the atmosphere.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and an object of the present invention is to provide a plastic film bag having tear tapes, which can be opened using the tear tapes and can be completely sealed despite the tear tapes being provided on the film bag.

The inventor provides a plastic film bag having tear tapes according to the present invention after actively studying a phenomenon in which, when molecules of a polypropylene film are oriented monodirectionally, the polypropylene film has the property of tearing straight in one direction. Described in detail, if tear tapes made of the monodirectionally oriented polypropylene film are attached to the outer surface of a plastic film bag using an adhesive, the plastic film bag may be cut straight in one direction when the tear tapes are pulled backwards along a predetermined tear line of the film bag.

In an aspect, the present invention provides a plastic film bag comprising a seam welded part, a plastic film bag body part and tear tapes to open the plastic film bag, wherein each of the tear tapes is made of a monodirectionally oriented polypropylene film and is attached to an outer surface of the plastic film bag using an adhesive at a predetermined position between the seam welded part and the plastic film bag body part.

In the plastic film bag, the plastic film of the plastic film bag may be selected from the group consisting of polyethylene films, polypropylene films, nylon films, polyester films, and papers impregnated with synthetic resin.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings.

FIG. 1 is a perspective view and isolated sectional view illustrating the construction of a conventional plastic film bag having tear tapes attached to respective inner surfaces of the bag.

FIG. 2 is a perspective view and isolated sectional view illustrating the construction of a plastic film bag having tear tapes attached to respective outer surfaces of the bag according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a plastic film bag which can be opened using tear tapes and can be completely sealed despite the tear tapes being provided on the film bag.

The plastic film bag according to the present invention will be described in detail with reference to FIG. 2.

In FIG. 2, the reference numeral 1 denotes a plastic film bag according to the present invention, 2 denotes a film bag body part, 3 and 3′ denote a tear tape, 4 and 4′ denote two seam welded parts, and 5 denotes a plastic fastener. In the present invention, the plastic film bag may be constructed without having the plastic fastener 5, unlike the preferred embodiment.

In the present invention, the plastic film, used as the material for the plastic film bag 1, may be selected from the group consisting of polyethylene films, polypropylene films, nylon films, polyester films, and papers impregnated with one of the above-mentioned synthetic resins which are polyethylene, polypropylene, nylon and polyester. Each of the tear tapes 3, 3′ is made of a monodirectionally oriented polypropylene film (herein below, referred simply as “MOPP film”).

Polypropylene resin is a crystalline polymer wherein propylene molecules are arrayed with stereo regularity.

Thus, when a rectangular polypropylene film is stretched in one direction, the propylene molecules of the film are oriented in the stretched direction while forming straight lines, thus becoming an MOPP film. When the MOPP film is cut in the oriented direction, the film is cut along the texture of the arrangement of the oriented propylene molecules.

In the present invention, a tear tape made of a MOPP film is attached to the outer surface of a plastic film bag using an adhesive along a predetermined tear line while considering the above-mentioned properties of the MOPP film. When the tear tape attached to the plastic film bag is pulled straight backwards, the tear tape is cut along the texture of the arrangement of the oriented propylene molecules and cuts the plastic film bag straight along the predetermined tear line, thus opening the plastic film bag.

The plastic film, used as the material of the plastic film bag according to the present invention, is preferably selected from films 100-200 μm in thickness. When a plastic film 100 μm in thickness is used, it is preferred to use a tear tape 5 μm in width and 30 μm in thickness, while, when a plastic film 200 μm in thickness is used, it is preferred to use a tear tape 6 μm in width and 70 μm in thickness.

Each of the tear tapes 3, 3′ is preferably attached using an adhesive to the outer surface of the plastic film bag body part 2 along a predetermined position between the upper seam welded part 4 and the body part 2.

In the present invention, well-known acryl resin-based adhesive or rubber-based adhesive is preferably used as the adhesive to attach the tear tapes on the outer surface of the plastic film bag.

In the plastic film bag having the above-mentioned construction according to the present invention, the tear tapes are characterized in that each of the tapes can tear straight along a predetermined tear line with a small force without using any additional cutting tool. Thus, when a user pulls the tear tape straight backwards with fingers holding an end of the tape, the plastic film bag, to which the tear tape is attached using an adhesive, is cut straight by the tear tape, thus being opened.

As apparent from the above description, the plastic film bag according to the present invention is realized such that tear tapes are attached to the outer surface of the plastic film bag using an adhesive. Thus, unlike a conventional tear tape attached to the inner surface of a plastic film bag, the tear tape of the present invention does not compromise the function of sealing the package, but allows the package to be completely sealed.

Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A plastic film bag comprising: a seam welded part, a plastic film bag body part, and a tear tape to open the plastic film bag body part, wherein the tear tape is comprised of a monodirectionally oriented polypropylene film and is attached to an outer surface of the plastic film bag body part at a predetermined position between the seam welded part and the plastic film bag body part.
 2. The plastic film bag as set forth in claim 1, wherein a plastic film of the plastic film bag body part is selected from the group consisting of polyethylene films, polypropylene films, nylon films, polyester films, and papers impregnated with synthetic resin. 